Background

The continuous decrease of coal production and envisaged phasing-out of subsidized hard coal mining reveals the management and possible utilization of unmined coal seams as major task in Germany and world wide. Substantial benefits can be gained from a system which provides economical and environmentally friendly energy supply combined with reduction of greenhouse gas emissions.

Flash Movie Principle of underground coal gasification with combined CO2 storage (UCG-CCS)

In-situ coal conversion, also addressed as underground coal gasification (UCG), is a technique that has been investigated and tested for several decades. While this technique was considered an environmental risk due to potential groundwater contamination for a long time, in recent years the advantages have come into the focus:

• no hazards from mining
• no disposal of ash or slurry
• emission reduction and maximum utilization of resources that cannot be mined economically.

Map World-wide underground coal gasification projects

Scientists have learned to constrain environmental hazards by new methods of UCG process control and an improved site selection. A current development is the connection of UCG with CO2 storage into the newly generated cavities. In recent years, both ideas – UCG and CO2 capture and storage (CCS) – have led to intensified research work and political activities in many countries.